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Unusual phenomenon

tonigau

Member
This is probably more of a physics topic ?
I received a gift of a nice old forklift battery charger, It got wet outside in the rain.
I observed the ammeter needle move when I touched the front , played around a bit & got inconsistent but repeatable needle movement & it would even hold a position, (doesnt seem like sticky pivot) .
There would be high humidity inside the meter as there is h2o condensate visible inside the meter front.
___ Strange.
After dry out it no longer reacts to touch.

Video attached

MVI_1163.mp4_snapshot.jpg
 

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JimB

Super Moderator
Most Helpful Member
I have seen this effect before, on several meters, each completely different form each other.

I believe that the effect is due to electrostatic charging of the meter "window".

JimB
 

unclejed613

Well-Known Member
Most Helpful Member
yes, electrostatic induction. the plastic (or on older meters, glass) acts as a dielectric, which charges up if you touch it with a static charge on your finger the charge inside acts on the needle and makes it move.
 
I had a grand old-shool volt meter (maybe ammeter?) but the glass was cracked. No problem I thought, and laser-cut an acrylic lens to replace the cracked glass one. A total bust. The electrostatic charge wouldn't even let the needle move.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I had a grand old-shool volt meter (maybe ammeter?) but the glass was cracked. No problem I thought, and laser-cut an acrylic lens to replace the cracked glass one. A total bust. The electrostatic charge wouldn't even let the needle move.
Yet most meters, including the one at the start of this thread, have plastic 'glass'.
 
In my case, the meter is 70+ years old. Glass lenses were the norm.

The lens I cut was plain old acrylic. I don't know what plastic is used in meters; perhaps it has antistatic properties. At any rate, I was just relating my failed attempt at creating a replacement lens.
 

atferrari

Well-Known Member
Most Helpful Member
Brushing my Kamoden HT-100B (bought it 45 ++ years ago), got this. Just by touching it with the palm of the other hand, it went to zero. A dry day here.
 

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atferrari

Well-Known Member
Most Helpful Member
Not in my place where high humidity is frequent, but in the flat part of Patagonia dry weather is quite common. I like that.

You suffer much less summer or winter.

The most impressive fog I encountered ashore was with our vessel alongside at Liverpool.
 

Pommie

Well-Known Member
Most Helpful Member
Don't understand most of your questions but
Now I live in Australia, I love rain. It was horrid and cold in the UK but now warm and nice.
We occasionally get low cloud (fog) but it tends to dissipate by about 8am.
The size Australia is, we get all types of weather.
Top part tropics, below just awesome.

Mike.
 

atferrari

Well-Known Member
Most Helpful Member
Don't understand most of your questions but
Now I live in Australia, I love rain. It was horrid and cold in the UK but now warm and nice.
We occasionally get low cloud (fog) but it tends to dissipate by about 8am.
The size Australia is, we get all types of weather.
Top part tropics, below just awesome.

Mike.
Is the above addressed to me, Mike?
Questions? I posed only one and Nigel answered already.
 

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